Cardiac Markers for Diagnosis of Acute
Myocardial Infarction
Clinical Chemistry Review 102
CK-MB MYOGLOBIN CARDIAC TROPONINS (cTn)
Elevation after chest pain 4–6 hr 1–4 hr 4–10 hr
Duration of elevation 2–3 days 18–24 hr 4–10 days
Sensitivity/specificity Not entirely specific for AMI Sensitive but not specific High sensitivity & specificity
Methods Immunoassay Immunoassay Immunoassay
Comments Used to be “gold standard.” Negative predictive marker. If not Considered definitive marker for AMI
Use declining because of ↑within 8 hr of chest pain,
newer tests AMI ruled out
Testing recommendations Use 2 biomarkers—1 that is ↑within 6 hr (CK-MB or myoglobin) & 1 with high sensitivity & specificity that
is ↑within 6–9 hr & remains elevated for several days (troponin). Draw blood at admission, at 6–9 hr, & at
12–24 hr, if previous results were not ↑
